This 37-slide teaching PowerPoint presentation covers 2.A.1 (Energy Input) in the AP Biology (2015) curriculum. Each slide includes the 'Essential Knowledge' being covered as well as key terms that students should make note of (editable).
The presentation itself contains minimal information as it is intended to be used with teacher guidance. There are 'Video' slides throughout which link to relevant and informative YouTube content. The slides are formatted to be visually pleasing and to also print well for handouts or revision.
**This presentation is based on the AP Biology Course Guide and does not follow any textbook
As always, please let me know if you have any suggestions for improvements. These are always a work in progress!
The Essential Knowledge covered includes:
2.A.1 - Input of Energy
All living systems require constant input of free energy.
a. Life requires a highly ordered system.
1. Order is maintained by constant free energy input into the system.
2. Loss of order or free energy flow results in death.
3. Increased disorder and entropy are offset by biological processes that maintain or increase order.
b. Living systems do not violate the second law of thermodynamics, which states that entropy increases over time.
1. Order is maintained by coupling cellular processes that increase entropy (and so have negative changes in free energy) with those that decrease entropy (and so have positive changes in free energy).
2. Energy input must exceed free energy lost to entropy to maintain order and power cellular processes.
3. Energetically favorable exergonic reactions, such as ATP/ADP, that have a negative change in free energy can be used to maintain or increase order in a system by being coupled with reactions that have a positive free energy change.
c. Energy-related pathways in biological systems are sequential and may be entered at multiple points in the pathway.
d. Organisms use free energy to maintain organization, grow and reproduce.
1. Organisms use various strategies to regulate body temperature and metabolism.
- Endothermy (the use of thermal energy generated by metabolism to maintain homeostatic body temperatures)
- Ectothermy (the use of external thermal energy to help regulate and maintain body temperature)
- Elevated floral temperatures in some plant species
2. Reproduction and rearing of offspring require free energy beyond that used for maintenance and growth. Different organisms use various reproductive strategies in response to energy availability.
- Seasonal reproduction in animals and plants
- Life-history strategy (biennial plants, reproductive diapause)
3. There is a relationship between metabolic rate per unit body mass and the size of multicellular organisms — generally, the smaller the organism, the higher the metabolic rate.
4. Excess acquired free energy versus required free energy expenditure results in energy storage or growth.
5. Insufficient acquired free energy versus required free energy expenditure results in loss of mass and, ultimately, the death of an organism.
e. Changes in free energy availability can result in changes in population size.
f. Changes in free energy availability can result in disruptions to an ecosystem.
- Change in the producer level can affect the number and size ofother trophic levels.